This invention relates to nuclear magnetic resonance spectroscopy and more particularly to a system for controlling the temperature of samples being tested in an NMR spectrometer.
Accurate sample temperature detection and maintenance can be critical during an NMR experiment. For example, biological samples may deterioriate rapidly if not held at or near their normal reaction temperature. Inorganic reactions can explode violently if not maintained slightly below their critical temperature. Yet to determine structure it may be required that the sample be studied at degrees or fractions of degrees below this critical temperature. However, since spinner apparatus is employed to rotate the samples at various speeds, and since temperature sensors disturb field homogeneity, temperature sensors are not usually able to be immersed in the sample during tests. Hence determination of sample temperature during NMR observation has been accomplished through the use of a sensor mounted adjacent the sample. The sensor is normally mounted in a position just slightly below the sample holder in the gas stream used to heat or cool the sample. Heat leaks prevent the sample and sensor from being the same temperature.